The present disclosure relates to an oil supply device that supplies oil to a vehicle drive device that includes an input member drivably coupled to an internal combustion engine, a rotary electric machine for driving wheels, an output member drivably coupled to the wheels, a speed change device that includes a shifting engagement device and that at least transfers rotation of the input member to the output member with the speed of the rotation changed, and a decoupling engagement device that decouples the input member from the speed change device.
The vehicle drive device described above can decouple the internal combustion engine from the wheels to suppress an energy loss due to a drag resistance of the internal combustion engine by controlling the decoupling engagement device to a disengaged state during execution of an electric travel mode in which the vehicle is driven by only torque of the rotary electric machine. An example of such a vehicle drive device is described in German Patent Application Publication No. 102009042933.
In the configuration described in German Patent Application Publication No. 102009042933, the vehicle drive device requires an increased amount of oil in the case where torque of the internal combustion engine is transferred to the wheels to drive the vehicle with the decoupling engagement device controlled to a slipping engagement state, for example, and a hydraulic pump driven by the internal combustion engine or the rotary electric machine is designed in accordance with the amount of oil for this case. In the case where the vehicle is driven in the electric travel mode, a reduced amount of oil is required by the vehicle drive device. In the configuration described in German Patent Application Publication No. 102009042933, however, it is necessary to drive the hydraulic pump, which is designed to be relatively large in size as described above, also in this case. Therefore, large torque is required to drive the hydraulic pump, which accordingly reduces the energy efficiency, compared to a case of driving a hydraulic pump designed in accordance with the amount of oil required when the vehicle drive device is in the electric travel mode. The technology according to German Patent Application Publication No. 102009042933 leaves room for improvement in this point.